Dexamethasone induces human glutathione S transferase alpha 1 (hGSTA1) expression through the activation of glucocorticoid receptor (hGR)

Putative response elements for several nuclear receptors, including the glucocorticoid receptor (GR), have been identified at the hGSTA1 gene promoter located at −896 bp, −863 bp and −727 bp from the transcription start site. After dexamethasone (DEX) treatment, the GR induces hGSTA1 expression at the transcriptional level. The characterisation of this effect reveals that the GR binds to several glucocorticoid response elements (GREs) located at the hGSTA1 gene promoter. This interaction also results in the transactivation of the hGSTA1 gene promoter together with an increase of the hGSTA1 mRNA levels as well as the protein and activity levels in HepG2 cells. Together, the present results suggest that glucocorticoids have the potential to alter the xenobiotic and endobiotic metabolism mediated by hGSTA1.